Curious beginning of life than that of jellyfish. In some species, the larvae resulting from fertilization attach themselves to the seabed, clone themselves and, like trees, bud and then detach to take on the appearance of the animals we know. Like the vast majority of living beings, these animals thus freed from their nurseries grow, age and finally die.
But one type of jellyfish, the immortal jellyfish, escapes fatality. The aptly named can indefinitely reverse the process, find a juvenile form in the form of a polyp, reattach itself to a wall and thus avoid death from old age. A team of researchers, led by biologist Maria Pascual-Torner from the University of Oviedo, Spain, set off in search of its secret of youth. In an article published at the end of August in the journal Proceedings of the National Academy of Sciences (PNAS), she delivers the results of her research.
To achieve their ends, the researchers sequenced the genome of Turritopsis dohrnii and compared it to that of a close species, known in English as the “crimson jelly”, a vulgar mortal. They found that the immortal jellyfish had twice as many copies of genes associated with DNA repair and protection. Duplicates that would explain a better production of beneficial proteins. Very specific mutations would also slow down cell division and cell aging, which is notably produced by the shortening of telomeres, the end of chromosomes.
A track against cancer?
When, weakened by an injury or a change of environment, the immortal jellyfish becomes a polyp again, its cells return to their primordial state, as on the first day. If it does not have the same capacity for regeneration, the crimson jellyfish, Turritopsis rubra, nevertheless has copies of the “magical” genes. She can get younger but not as often as her “cousin”.
According to the team of scientists, the genes identified could provide information on age-related diseases in humans, such as neurodegeneration or cancer. Or even inspire regenerative medicine. At the Institute of Functional Genomics at the University of Montpellier in France, work is being done, for example, on reversing the aging process of cells or destroying senescent cells responsible for the appearance of tumours. With promising results.
Immortal jellyfish are not the only ones with this power. Last June, a study published in Science explained that certain species of reptiles and amphibians do not age.